I order canada goose trillium size xs but the waist is too tight for me, I'm 5'6 and 125lbs what size do you think will fit me for kensington?

Tech Specs:

Material:

[shell] Arctic-Tech (85% polyester, 15% cotton), DWR coating; [lining] plainweave nylon, WR coated 

Insulation:

625-fill white duck down 

Fabric Waterproof Rating:

water-resistant 

Hood:

yes, adjustable, , insulated, , fleece-lined, , removable coyote-fur accent 

Fit:

regular 

Center Back Length:

37.75 in 

Length:

thigh 

Pockets:

2 handwarmer, 2 lower fleece-lined snap closure 

Recommended Use:

winter casual, high fashion insulation, apres ski attire 

Manufacturer Warranty:

lifetime